1. Field
Exemplary embodiments of the invention relate to a backlight unit used in a curved surface display device, which is capable of improving surface flatness of a light source cover.
2. Description of the Related Art
A liquid crystal display (“LCD”) is a type of flat panel display (“FPD”), which is most widely used as a display device. The LCD includes two substrates on which an electric field generating electrode such as a pixel electrode and a common electrode is disposed, and a liquid crystal layer interposed between the two substrates. In the LCD, a voltage is applied to the electric field generating electrode so that liquid crystal molecules of the liquid crystal layer are rearranged, thereby adjusting the amount of transmitted light.
LCDs are used as a display device in a wide range of applications including televisions and also are available in a wide range of screen sizes. Depending on positions at which a viewer sees a central portion of a screen or left and right end portions thereof, a visual disparity becomes disadvantageously larger as the screen size of LCDs is increased.
In order to compensate for the visual disparity, a curved surface display device has been developed, of which a surface is curved in a partial-circle profile extending from a central portion of a display area to each of opposing sides of the central portion.
The curved surface display device can be classified into two categories: a portrait type that has a longer vertical length than a horizontal length from the viewpoint of a viewer and is curved in a vertical direction, and a landscape type that has a longer horizontal length than a vertical length from the viewpoint of a viewer and is curved in a horizontal direction.
The curved surface display device includes a backlight unit that is curved to fit a shape of a curved surface thereof. The backlight unit is classified into three types: a direct type, an edge type and a corner type, based on the position of a light source.